A watertight argument

It’s a familiar scenario, builders who choose the cheapest possible waterproofing ‘solution’ and then live to regret it when their installed system fails. The resulting leaks, dampness, concrete spalling, ugly staining then need to be fixed, a costly process. In fact, it is estimated that 60-80 percent of all building claims result from poor waterproofing choices.

While an effective waterproofing solution, properly installed during construction costs little more than one percent of a typical construction budget, John Martin, marketing manager for waterproofing at Parchem Construction Products says too many builders are still seeking to cut waterproofing costs as part of a broader cost minimisation strategy. “It’s the wrong place to be looking for a cost saving,” he argues. “It’s one percent of the total project cost. It causes 60-80 percent of failures. Why would you go cutting costs in those areas?”

The key consideration, he believes, is one of risk assessment, which means considering more than simply considering the up-front installation costs. Important decisions, thereforem need to be made before beginning any waterproofing work, beginning with an assessment of the value of particular products on offer rather than simply their relative costs.

Specifications for waterproofing products should contain a number of clearly identified performance requirements, rather than the all too common ‘name of a product or equivalent.’

“That’s not a specification,” says Martin. “They need to say that the waterproofing should have a certain thickness, and be able to accommodate a certain amount of elasticity, be supported by a certain number of similar projects - a certain number of actual performance specifications.”

Martin cites the recent Murray Street, Woolworths building in Perth as an example of a highly demanding - a basement below the water table - but totally successful waterproofing project. “There wasn’t a single leak in that whole structure, because we were on site on a regular basis, we helped oversee it, we trained the people that installed it and we supported them through every step of the process.”

Parchem offers a full range of waterproofing products including sheet membranes, liquid-applied membranes, cementitious systems and concrete admixtures such as Emer-Clad, Fosroc, Index, TEMA and Vandex.